Ethnomedicinal uses, phytochemical characterization, and antibacterial activity of Grewia tenax and Albizia anthelmintica extracts against multidrug-resistant pneumonia-causing bacteria

Abstract

The use of Grewia tenax and Albizia anthelmintica in treating different ailments is attracting significant attention as a primary health care option in Namibia. This study aims to document their ethnobotanical uses, phytochemical composition, antioxidant, and antibacterial activity against multidrug-resistant Streptococcus pneumonia, Klebsiella pneumonia, and Staphylococcus aureus. The ethnobotanical uses of G. tenax and A. anthelmintica in treating respiratory conditions were documented. Organic (ethyl acetate) and aqueous extracts were screened for phytochemical composition using the thin-layer chromatography method. The total phenol content was determined using the Folin and Ciocalteu reagent method. In vitro antioxidant activity was based on the scavenging activity of the stable 1, 1-diphenyl 2-picrylhyorazyl free radical. Antibacterial activity of extracts (200.0 µg/ml) and antibiotics was determined by the disc diffusion method. G. tenax and A. anthelmintica are commonly used to treat pneumonic symptoms. Steam inhalation and decoction are the most common methods used in preparing remedies. While alkaloid, flavonoid, and coumarins were detected in all extracts, organic extract of A. anthelmintica showed higher total phenol content of 28.5 ± 0. 5 mg GAE/g. G. tenax organic extract showed higher in-vitro antioxidant activity of 83.3±0.1%. The pathogens showed resistance to 10 µg of penicillin G, and Co-Trimoxazol, however, A. anthelmintica organic twig extracts inhibited the growth of the bacteria with average inhibition ranging between 17.5±0.6 - 20.7±0.6, mm and a minimum inhibitory concentration of 50.0 µg/mL. These findings are the first to report on the ethnomedicine of G. tenax and A. anthelmintica in Namibia and their effectiveness in killing pneumonia-causing bacteria. Key words: Phytochemical screening, total phenol content, antioxidant activity, antibacterial activity, pneumonia, antibiotic resistance, G. tenax, A. anthelmintica.